Dr. Ruth Yanai requests for Research Experience for Undergraduates (REU) and Research
Opportunity Award (ROA) have been recommended for funding this summer.
Through this funding, participants work with multiple investigators,
assisting with on going research, and also developing individual
projects that they will see to completion.

REU Proposal:

The
project on Multiple Element Limitation in Northern Hardwood Ecosystems (MELNHE)
provides excellent opportunities for exposure to scientific research
because it involves so many researchers and so many topic areas, with
work centered in an attractive geographic location that promotes
interaction. In addition to the nine stands of three ages at Bartlett
originally funded by NSF, we are working in young and mature stands at
Jeffers Brook and Hubbard Brook, which provide a gradient in site
fertility. There were five PIs initially funded on collaborative
proposals, and four more have written other proposals to fund their work
in our sites. There are five graduate students currently funded on the
main project and more are being recruited. There are undergraduates on
the field crew, each with responsibility for a project area, and there
is a constant flow of visiting scientists, foreign exchange students,
and visitors from other projects. The center of activity is the White
House at Bartlett, with the nearby dorm and lab. Sharing housing,
meals, and cooking responsibilities contributes to the chances for
interactions with scientists at all levels of development.

Because of the large number of researchers involved, REU participants
will have the opportunity to learn about and contribute to a wide
variety of measurements at these sites, including tree inventory, herb
and seedling inventory, root biomass, root imaging, soil sampling, soil
respiration, nitrogen mineralization, leaf area, collecting litterfall,
and shooting fresh foliage. There are opportunities for laboratory
experiments, for example on nitrogen mineralization and microbial
respiration, as well as field experiments. They will also have access
to reams of data collected during the previous funding cycle at Bartlett
(http://www.esf.edu/MELNHE)
and collected over decades at the Hubbard Brook Experimental Forest (http://www.hubbardbrook.org/data/dataset_search.php).

We
hope to have additional REU students on our team at Bartlett, supported
on the HBR LTER or by the REU Site at Plymouth State University, if
renewed. Regardless of how they are funded, we treat all our team
members as researchers, not just as grunt labor, and we give them the
support they need to learn about experimental design, research planning,
time management, project coordination, data analysis, and the scientific
communication of results. The integration of efforts across a range of
backgrounds and experiences, from REU, to RET, to visiting professors,
provides everyone an opportunity to better understand the process of
scientific research, and everyone gains exposure to a wide range of
subjects within the fields of forest ecology and ecosystem nutrient
cycling.

Possible projects
Participants
in this year’s field operations will develop focused research projects
in the context of the overall experimental design. Some possible
projects are listed here.

Impact of
fertilization on soil nitrogen transformations using laboratory
incubations: The student can examine questions relating to changes
in decomposition rates and in nitrogen mineralization and
nitrification rates resulting from N and P fertilization. We have
pre-treatment results as well as results from similar factorial
experiments where nutrients were added in the lab, and the student
can compare their results to this previous work.

Filming
minirhizotrons can tell us the effect of nutrient treatments on root
production. Calculations of root turnover can make use of root
biomass measured in 2009 in power-cored samples at depths > 30 cm
and soil cores for shallow root biomass (0-30 cm). Root biomass
and production can thus be compared by soil depth, forest age, and
across sites.

Heterotrophic
respiration: In 2009, we trenched plots in five stands to exclude
roots. This year, a comparison of soil respiration in the trenched
plots and outside the plots permits an estimate of autotropic and
heterotrophic respiration. The four plots in each stand should be
compared to see if there is already a response to nutrient additions
in young and old stand in two contrasting sites.

The development of
leaf area could be monitored using an LAI-2000. We will be
monitoring sap flow in some of our stands to test for an increased
in transpiration in response to nutrient additions, as observed in
the whole-watershed Ca addition at Hubbard Brook. Differences in
leaf area development with treatment could be important to
explaining changes in transpiration following nutrient additions.

Northern red oak is
an infrequent associate of northern hardwood species in our
permanent plots. In a warming climate, we expect this species range
to expand. Monitoring oak regeneration could give us an early
signal of response to climate change. We have regeneration data from
the 1990s to which to compare current data.

Forest productivity:
We will inventory trees on all our plots this year, the first year
of treatment. We need to test whether growth differs already by
treatment compared to earlier inventories, or whether these data can
be used as a baseline to detect future changes in productivity.
This project would include field work (with a large crew), data
entry, documentation of methods and data, and statistical analysis.

Forest composition:
The results of stand inventory can also be used to describe forest
community structures through non-parametric multivariate analysis
such as Canonical Correspondence Analysis or Non-Metric
Multidimensional Scaling. We have data on environmental variables
such as soil chemistry, soil depth, aspect, slope and elevation that
could be used in the multivariate analysis to explore causes of the
variation in forest structure.

Other program elementsWe have developed a culture for mentoring students and
developing skills essential to the conduct of scientific research and a
spirit of cooperation in the field crew. Some of the program elements
are outlined below. New this year will be a weekly seminar series,
based on the successful Science Night tradition at Hubbard Brook.

Proposals for each
research project will be developed by the leading student and
reviewed by the team. Approved proposals will be posted on our web
site prior to initiation of the work. Formal review of proposals
can prevent many misunderstandings and errors in implementation.

Each REU will be
mentored by a graduate student. They will be mentored in several
areas relating to their individual research, including proposal
preparation, data collection, organization, and documentation, and
statistical analysis.

Each REU will give
an oral presentation at the annual Hubbard Brook Cooperators meeting
in July. Many of our undergraduates have made presentations at this
meeting, including three last year.

An important
component of the summer experience is the shared living experience,
including cooking (in teams of two), eating together, and household
chores. We have a wide variety of experience and cultural
backgrounds represented on the team, and we learn from each other in
professional, social, and personal arenas.

Thursday night
discussion series: Herb Bormann and Tony Federer have already
agreed to give presentations; many other prominent researchers work
at Bartlett who are not associated with our project (Scott Ollinger,
Andrew Richardson, Dave Hollinger, Bill Leak), and we will schedule
them to give presentations on their work in conjunction with their
travel to Bartlett. In alternation with these presentations, we
will discuss reading of common interest, including topics such as
the impacts of scientific research on society.

Results
from previous REU Supplements

This is
our first request on the current grant. The previous grant for work on
this project (DEB-0235650) supported several REU students. Their
projects included an analysis of change in forest floor depth, using
long-term remeasurement; analysis of roots collected from quantitative
soil pits, contributing to a publication; and a satellite project
exploring the long-term effect of liming on N mineralization and P
availability. Most of these students made presentations at the annual
Cooperators’ Meeting of the Hubbard Brook Ecosystem Study, and several
used their research projects as the basis for Senior Theses.

DiversityThe
crew leader at our field site is a woman, Corrie Blodgett (a veteran of
our 2004 field crew, when she was an undergraduate). The majority of
our current graduate students (4 out of 5) are women. Half of the 6 PIs
are women, including two in leadership positions. Thus the male and
female students on the crew will be exposed to both female and male role
models. This is important for students from institutions such as ESF,
which still has only 15% women on the faculty. We also benefit from
broad cultural diversity, with students hailing from Puerto Rico, China,
and Korea, as well as the mainland US.

Participant selectionWe
will select students based on academic and career interests, previous
academic course work and field experience, and aptitude for research.
We have contact with many potential students through teaching and
academic year lab employment; where we don’t have first-hand knowledge
of student ability and interests, we will interview their referees,
rather than relying solely on written references.